Question

Calcule :
a) 2 (-3x+4) -9 = 3(4x-7)

b) 5x-9+8x+5=-2x + 7 -4x

Answer 1

a) 2 (-3x+4) -9 = 3(4x-7)
-6x + 8 -9 = 12x - 21
8 -9 + 21 = 12x +6x
20 = 18x
20/18 = x

b) 5x-9+8x+5 = -2x + 7 -4x
5x + 8x +2x + 4x = 7 +9 - 5
19x = 11
x = 11/19

Answer 2

2 (-3 x + 4 ) - 9 = 3 (4 x - 7 ) = 
-6 x + 8 - 9 = 12 x - 21 = 
-6 x - 12 x = -21 -8 + 9
-18 x = -29 + 9
-18 x = - 20 
x = -20/-18
x = 10/9

b)5 x - 9 + 8 x + 5 = - 2 x + 7 - 4 x
5 x + 8 x + 2 x - 4 =  +7 - 4 x
13 x + 2 x + 4 x = +7 + 4
13 x + 6 x = 11
19 x = 11 
x = 11/19